Automatic fire alarm



June 25, 1929. o. B. ELLIOTT 1,718,857

AUTOMATIC FIRE ALARM v Filed 0G12. 23, 1920 a M 4% O zaaa,

Y rasata" .time 295,' i929.

` I l 1,718,857 L UNITED- sTATEssPATENT-L-QFFCEfyo'rro BREEDON ELLIOTT,or DUNEDIN, NEwzEL'LAND.

AUToMA'rIc man l Appunti@ md oc'tberza, 1920, seria: 10.419,012, nain mwzealand necemb'er 22, 1919.

This invention relates .tofautomatic electrlcal lire alarms-wherebybupon a fire occurring, the annunclatlon 1s ygwen by the actionof a thermostat operating upon certain de-4 grecs of heat to openand'close ya plurality of `circuits includingeletromagnetic devices for'Vina alarms.

mally.closed circuit which will give a pre-` and the like, orthat analarm is about to be given.

The object vof the present invention is `to 'provide an improved alarmwhereby certain faults in the circuits, such as'short circuits, brokenlines, and run down batteries, are indicated instantly-at theinstallation, and at the same time leaving the installation in suchorder thatin the event. of a lire theyalarm will be given.

The electrical thermostatic alarm system embodying the present inventioncomprises a combined normally. closed circuit and an -open circuit,1..analarm controlling means therefor operated in twostepsl by successivechanges in the electrical condition of said cirg .cuits andthermostatieally controlled means for producing such changes.

The first' change in the electrical condition of said circuits, is thebreaking of the norliminary alarm or visible signal to a watchman of abuilding or other place Iof installa-- tion of the system, that a faultexists in the line such as run-down batteries, broken lines This lclosedcircuit will prevent the accidental closing of the open circuit, such ascrossing of the lines of said open circuit, a ground or a similar changein its electrical' condition which may be caused by electrical 4stormsand which changes would obviously render a false alarm forunnecessarilyl calling outthe'reJorigade. v

The second change in the system is the closing of the open circuit-whichshould happen only when a lire occurs and this :open clrcuit has anumber of electrlcal conductors greater than two, and each commonthere-V in a simplified manner.

y duct/ors will function to establish a circuitous path for theelectrical `energy lin order to `close an'alarmcircuit, which latter mayin` clude a suitable alarm signal ortransmitter p, wherebyproperannouncement will be made f to the re brigade station that a fireexists.

In the drawings the'single figure is a dia- "grammatic View illustratingthe arrangement and connections of the various parts,

connected contacts 8 and 9. Mounted spaced from the contact 8 is an opencircuit contact 10. The arrangement of these contacts and strip 5 gagescontact 8 and in its initial movement is such that t-he strip normallyen will break engagement with contact 8 and engage contact 10. Finalmovementv of the arm 2 will bow. strip 5 and thereby bridge the distancebetween contacts 9 and 10.`

The system has included' therein, a'drop switch comprising a coil 11,magnet 12,'

4switch blade 13,` and'release arm 14 forced to a releasing .position bythe spring 15 upon.- deenergization of the magnet 12. A control switch16 is provided which also includes. a

lmagnet 17, arm 18 actuated by spring 19 and a switch blade 20. It willbe noted that the arm 14 of drop switch is mounted to operate when themagnet 12 is energized whereas the arm 18\ is mounted to release uponenergization of magnet 17, whereby magnet 12 is normally energized andmagnet 17 normally deenergized. Switch blade 20 normally breaks thesignal circuit 21 which may be of any well known type but illustrated asa gong 22 energized by the battery 23.

.Av circuit breaker 24 is arranged within and adapted under certainconditions to break the vclosed circuit 25 by releasing the arm 26 thatbridges a break in the circuit.. The closed circuit includes a source ofcurrent 27 having a wire 40 leading therefrom tothecoi-l 24 of a circuitbreaker and from this coil 24 this conductor 40 extends to the terminal6. A re turn Wire 41 extends from a contactS upon the plate whichsupports the two electrically connected contacts 8 and 9 and as theblade 5 is normally in'co'ntact with this contact 8, the

l"current will be permitted to flow through the conductor 41 to the coil11 of the drop switch aid'from thiscoil 11 of the drop switch thereturn'iwire extends to the circuit breaker 26 and ed in h avy lines inorder to distinguish it from the open circuit to be later described. Thewires 28 and-30 as hereinshown are ar- .then to the battery 27. Theclosed circuit, as yherein siwn upon the drawings is represent- 40 and41, but properly insulated therefrom.

I' y lthermostat has electrically ranged in the same cable or sheath asthe wires the two wires indicated y the numerals 28 and which areconnected at the point 43 and from this point of connection 43 a line 44extends to the coil 16 ofthe drop switch included in the alarm systemand from this coil 16 a return wire 45 leads to the battery 29. Aconductor 31` connects the contact 32 of the drop Avswitch included inthe open circuit with the wire 42 leading from the batter 29', whereasthe wire 33 connects the switch lade 13 with the wire 41 of the closedcircuit.

With a view towards providing a most dependable fire alarm s stem, thewire of the main circuit 25 is pre erably arranged in the same cable orsheath with the return wires which connect to contact 10, whereby uponrupture of a return wire the main circuit will also, in all probability,be ruptured, causing ghe irop switch 13 to fall, thus indicating such aut.

In the operation of the systemarm 2 normally assumes 4a position to holdthe strip 5 in engagement with contact 8 and thus the circuit 25 isnormally closed allowing current fro lthe battery `27 to pass throughmagnet 12i order to energize the circuit breaker 24. Upon battery 27becoming exhausted magnet 12 will become deenergized for allowing thedrop switch 13 to fall, thereby giving a visual indication of a fault inthe line and circuit breaker 24 will open for holding circuit 25 in anopen position. This same effect, will take place upon rupture anywherein themain circuit 25. Upon the temperature in the vicinity of thethermostat rising above a predetermmed degree, a difference in expansionof ,the elements 3 and 4 will cause the arm 2 to -move to a position tothrow the strip 5 into engagement with the contact 10 thereby breakingcircuit 25 and closing the normally open circuit, passing current fromthe battery 29 through magnet 17 of the control switch and therebyattract arm 18 releasing switch blade 20 for closing the signal circuitfor giving an alarm. l i

From the foregoing, it is obvious that be.-

yfore the open circuit can be brou ht into play, it is absolutelynecessary that t 1e closed cir`` cuit be broken, and when this closedcircuit is g broken, a lsuitable signal will be Agiven by the fall oftheblade 13 of the drop switch or by an annunciator associated therewith,that a fault exists within thefclosed, circuitfwhich fault must be'rectified in order to maintain the system in proper working condition.So long as this closed circuit is 1n' pro er order,

'the drop switch 13. will be retained 1n the position as 'shown linthevdraw ings, whereupon it should any ofthe wires of the o en circuitbe crossed or otherwise accidental connected. When a lire occurs, thestrip or b ade 5 of the thermostat will leave the contact 8, therebybreaking thcnormally closed circuit and permitting the blade 13 ofthedrop switch to touch the contact 32 and as the closed circuit is nowopen, the second change in this system is permitted to take placewhereinthe open circuit ma /be closed and the alarm given. Owing to te'arrahgement `of the several conductors included inthis open circuit,the current from the batter 29 is ermitted to 'pass through fourdistinct circuits in order to bring the alarm circuit into play and thepath of travel of electrical energy from the battery 29 over thesevarious circuits will now be described.

The first open circuit: The closed circuit being broken, the blade 5will touch the contact 10 of the thermostat when heat is applied to thelatter, whereby current muy flow from the battery 29 through the wires42, 4Q to blade 5 through contact 10 to conductor" 28, through coil 16of the drop switch of the alarm circuit and return to battery 29 throughthe conductor 45. Should, however, the conductor X28 become brokenV thecurrent from the battery 29wil1 take the second circuitous path whic maynow be called the second open circuit.

The second open circuit: The current from the battery 29 will passthrough the conductors 42, 40 to blade 5 of the thermostat to contact10, through conductor 30 to the coil 16 of the drop switch included inthe alarm circuit and return by the wire or conductor 45 to the battery29.. Should, however, both of the conductors 40 and 28 which areincluded in the same cable, become broken, the current from the battery29 may pass through the third open circuit.

Thethird open circuit: The fire still raging, will, of course, applyadditional heat to the thermostat, whereby the blade 5 will bridge thecontacts 9 and 10, whereupon the current from the battery 29 will passthrough the conductors 42, 31 switch blade 13 of the drop switch,Athrough the conductor 41 to the electrically connected contacts 8 and9, from the contactlU the current will flow over the. conductor 30 tothe coil 16 of the drop switch included i'n thealarm circuit. and fromthe coil 16 thecurrent' may return to the battery 29 through theconductor 45. However, should the'conductors 30 and 41 be broken,the-current. from the battery 29 may flow through in establishing thiscircuit, owsover the congle thermostat indicated by the numeral 1, it

is of course, to be understood that any number of these thermostats maybe employed as required by the place'of installation and suchtliermostats must be connected in series. The

circuit breaker-"26 remains vopen after the closed circuit has beenbroken and must be Y manually reset before this Vclosed circuit isagainbrought into use, but should a fire take f place, the closedcircuitwill remain open until one of the open circuits as previously described,has been closed in order to effect the 20 alarm. This closed circuit,however, may

have a suitable signalling device attached to the drop switch thereofwhereby an attendant'at the switch board of the building or i otherplace where installation has been ef-' 25 fected, will be immediatelynotied'of a. fault existing in the closed circuit line or a suitabletransmitter maybe connected thereto whereby a signal will be given tothe fire brigade station should any one of the open circuits 30 fail toactuate the; drop switch of t-lie alarm circui. Also, the alarm circuitmay include a suitable transmitter whereby the alarm may be transmittedto a brigade station.

' It is of course to be understood that various 35,0tlier forms ofthermostatic devices may be used in any number depending upon the areato be protected. It is also to be understood that variousother forms of'circuit maflbe used for connecting the various electro me- 40 chanicaldevices together. Therefore,- I do not desire to be limited in anymanner except as set forth in the following claims.

I claim:

1. An automatic fire alarm system comprising a closed'circuit, an opencircuit, an alarm device, thermostatically controlled means forproducing changes in said circuits, control- "ling means for said alarmdevice operated by a change `in said open circuit whereby to directlyeffect an alarm, and means included in said open circuit for permittingsaid change to ltake place therein only after a change has taken placein said closed circuit. i

2. An automatic tire alarm system compris- .55 ing a closed circuit, anopen circuit, an alarm device, means for controlling said alarm deviceoperated by the successive changes in the electrical conditions of saidcircuits, thermost'at'ically controlled .-means for producing 0 saidchanges, said open and closed circuits being constituted by a number ofelectrical conductors greater than two and eachof said conductors beingcommon to said open circuit whereby in failure of one or more of saidconductors to function a circuitous path of elecsaid conductors beingpositioned at points retrical energy will be established over the re-jmaining unimpaired conductors to cause said Y controlling means to beoperated when'said thermostatically controlled means effects a changewithin said open circuitand several of mote` from one another.

3.l An automatic firealarm system comprisf ing a closed circu'it,.anopen circuit,an alarmg device, means for, controlling said alarm de viceoperable only by a change in said open circuit whereby 4to effect thealarm, means` controllable by said closed circuit for" per- Vj 'mittinga change to take place iii said open circuit and tliermostaticallycontrolledineans A or producing said changes in the opened ,and. closedcircuits. l i 4. An automatic lire alarm system comprising a-closedcircuit, an open circuit, an alarm device, means for controlling saidalarm device operable by a change in said open circuit, a drop switchincluded in said open circuit, means included in said closed circuitfor-actuating said drop switch whereby a change in said open circuit maybe permitted, a circuit breaker included in said 'closed circuit,thermostatically controlled meansv adapted to rst 'effect a change insaid closed circuit whereby said drop switch will be operated for'permitting a change to take place Within' said open circuit and saidcircuit breaker operated to cause saidclosed circuit to remain open andsaid thermostatically controlled means adapted to subsequently eiect achange in said open circuit whereby said alarm device will be operated.

5. An automatic re alarm system comprising in ccmbination athermostatically controlled switch having a movableblade, a closedcircuit contact, a secondary closed circuit contact, an open circuitContact, said blade adapted to bridge said secondary closed circuit andopened circuit contacts, a closed circuit including conductorselectrically. connected with said blade and said closed circuit 1mcontacts, an open circuit, an alarm device, means for controlling saidalarm device operated by a change in the electrical condition of saidopen circuit, a source of electrical energy included in said opencircuit, a conductor leading from said source of electrical energy andadapted to be electrically connected to the conductors of the closedcircuit,

a conductor leading from the open contact of said .thermostaticallycontrolled switch and electrically connected to said'source ofelectrical energy, a drop switch included in said open circuit andymeans included in said closed circuit adapted to be actuated by achange in -said latter circuit whereby said drop switch will bepermitted to, form an L.'

electrical connection between the conductor leading' from said'source ofelectrical energy and one ofthe conductors of said closed circuit.

, 6. n automatic lire alarm system compris- I ing athermostatic switch`having a movable j anim/'a closed circuit contact mounted on one sideof said arm and normally engaged by vthe latter, and an open circuitcontact and a secondary contact arranged on the opposite side of saidarm, said secondary con-tact being electrically connected to said closed.circuiti contact and terminating at a point lower than the open circuitcontact, said open circuit and'secondary contacts adapted .to besuccessively engaged by said varm upon leaving the circuit having aleadconductor electrically closed circuit Contact; a 'closed circuitincluding said closed circuit contact, the coil of an electro-magneticdrop switch,a source of current and said movable arm a iirst alarm openconnected to the closed circuit at a point between the source of currentwithin said closed circuit and-saidclosed circuit contact, a returnconductor connectedl to said open circuit contact and the latter havingthe coil of an.-

' other electro-magnetic drop switch therein a circuit closed bysaidvlast mentioned'drop switch upon operation thereof for operating analarm; -and,a secondary alarm open circu'it including` said movable arm,said open circuit-and secondary contacts, said'iirst alarm open circuitand -the lead conductor of said first alarm open circuit being connectedto the closed circuit by vmeans of the iirst mentioned drop switch at apoint between said secondary contact and the coil of the, iirstmentioneddrop switch.

open circuit, means included in said closed circuit for maintaining saiddrop switch in an open position wherebya change will be necessaryin,said closed circuit inorder that said dro switch may assume a closedposition wit in said open circuit, a conductor included in said closedcircuit and connected to said blade of the thermost-atic switch, anotherconductor included in said closed circuit and electrically connected tosaid main and auxiliary closed circuit contacts, a battery included in,said'opencircuig a\conductcr leading from said battery' and,electrically connected to the conductors of the closed circuit, areturn-conductor electrically connecting said open ycircuit contact withsaid battery, said blade normally engaging said mam closed circuitcontact, said blade adapted to cause said closed circuit to be brokenupon leaving said main closed circuit contact and close said opencircuit upon touching said open circuit contact whereby saidcontrollingr means for the alarm device may be operated.

v8. An automatic fire alarm system compris- 'sing a closed circuit, anopen circuit, an alarm device, controlling means for said alarm dev1ceoperable only by a change 1n saxdopen c1rcu1t, means included '1n saldclosed circuit Ifqr permitting a change to take place in said saidcontrolling means of the device may be operated, said open and closedcircuits comprising a plurality of conductors over any two of which thecurrent in the open circuit may pass should a fault arise in theremaining` conductors said conductors being arranged in pairs and eachpair of conductors being positioned at points remote from one-another.

` In witness whereof I have hereunto set my hand.

ofrro BREEDQN ELLIOTT.

